Frequent blank page when first opening site?

I have installed the Suse 10 perfect install and then ISPConfig and things seem to be working correctly but I am haveing trouble with a blank page being served to users when they first arrive at a site. I currently have 3 sites running and one has the issue and the other doesn't seem to. The first is a mambo 4.5.2 site that works fine after a refresh but initially shows a blank page when going to the site. The other is a normal .html based site and doesn't seem to have any trouble. Now it is happening almost everytime you go to the site. The index.php page is shown with nothing displayed. I have placed an index.html with a meta refresh to the index.php in an attempt to get around this temporarily but it is not not doing the job. I have checked in the ispconfig vhosts file and it does have all the info I would expect regarding allowed directory index page types but still the issue. Any ideas would be appreciated. you can see the issue at www dot legacychurchofchrist dot org.

Thanks much in advance.

PAST UPDATE: I have removed the .html redirect and it seems to be working correctly again but this has changed once before. Has anyone else experienced an odd behavior such as this before?

UPDATE: It is now happening again, either way I do it. Is there some form of caching on the server I need to configure differntly for MAMBO on this server?